{"id":"CVE-2021-20022","kind":"vulnerability","aliases":["CVE-2021-20022"],"related":[],"title":"SonicWall SonicWall Email Security: SonicWall Email Security Unrestricted Upload of File Vulnerability","description":"SonicWall Email Security contains an unrestricted upload of file with dangerous type vulnerability that allows a post-authenticated attacker to upload a file to the remote host. This vulnerability has known usage in a SonicWall Email Security exploit chain along with CVE-2021-20021 and CVE-2021-20023 to achieve privilege escalation.\n\nCISA required action: Apply updates per vendor instructions.","summary":"SonicWall Email Security has an unrestricted file upload flaw that lets an authenticated attacker upload a file to the appliance. It is used in a exploit chain with CVE-2021-20021 and CVE-2021-20023 to escalate privileges.","severity":"high","cvss":7.5,"epss":0.16639,"exploited":true,"exploited_at":"2021-11-03T00:00:00+00:00","products":[{"name":"SonicWall SonicWall Email Security","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["email-security","exploited","ransomware","self-hosted","sonicwall","vendor"],"not_affected_if":["managed-hosting","unpatched-versions-not-in-use"],"how_to_check":null,"fix":"Apply updates per vendor instructions (SonicWall advisory for the Email Security product).","status":"open","published_at":"2021-04-09T18:15:13+00:00","first_seen_at":"2026-10-23T19:11:53+00:00","triaged_at":"2026-10-23T21:43:39+00:00","updated_at":"2026-10-23T21:57:34+00:00","category":"vendor","confidence":0.6,"triage":{"at":"2026-10-23T21:43:39Z","model":"claude-haiku-5-5","output":{"fix":"Apply updates per vendor instructions (SonicWall advisory for the Email Security product).","reach":"network","impact":"high","summary":"SonicWall Email Security has an unrestricted file upload flaw that lets an authenticated attacker upload a file to the appliance. It is used in a exploit chain with CVE-2021-20021 and CVE-2021-20023 to escalate privileges.","category":"vendor","who_cares":["sonicwall","email-security","self-hosted"],"confidence":0.6,"needs_auth":"yes","worst_case":"attacker uploads files to the appliance and escalates privileges as part of a chain","analyst_note":"Find the SonicWall advisory listing affected and fixed Email Security versions and the exact patch list; the sources here do not give them.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["unpatched-versions-not-in-use","managed-hosting"],"user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.00047,"input_tokens":2915,"output_tokens":356,"severity_before":"unknown"},"analyst_status":"queued","analyst_note":"Find the SonicWall advisory listing affected and fixed Email Security versions and the exact patch list; the sources here do not give them.","search":"'-20021':63B,115C '-20022':15A,18A '-20023':67B,119C '-2021':14A,17A,62B,66B,114C,118C 'achiev':121C 'action':126C 'allow':85C 'along':111C 'appli':127C 'applianc':52B 'attack':46B,90C 'authent':45B,89C 'chain':59B,110C 'cisa':124C 'contain':74C 'cve':13A,16A,61B,65B,113C,117C 'danger':81C 'email':3A,6A,21A,24B,34B,72C,107C 'email-secur':23B 'escal':69B,123C 'exploit':26B,58B,109C 'file':11A,39B,49B,79C,94C 'flaw':41B 'host':30B,98C 'instruct':131C 'known':102C 'let':43B 'per':129C 'post':88C 'post-authent':87C 'privileg':70B,122C 'ransomwar':27B 'remot':97C 'requir':125C 'secur':4A,7A,25B,35B,73C,108C 'security':22A 'self':29B 'self-host':28B 'sonicwal':1A,2A,5A,31B,33B,71C,106C 'sonicwall':19A,20A 'type':82C 'unrestrict':8A,38B,76C 'updat':128C 'upload':9A,40B,47B,77C,92C 'usag':103C 'use':55B 'vendor':32B,130C 'vulner':12A,83C,100C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2021-04-09T18:15:13+00:00","kev":{"dateAdded":"2021-11-03","dueDate":"2021-11-17","requiredAction":"Apply updates per vendor instructions.","knownRansomwareCampaignUse":"Known"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H","cvss_by":"nvd@nist.gov","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2021-20022","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-20022","severity":null,"published_at":"2021-11-03T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:53+00:00","fetched_at":"2026-10-25T16:39:50+00:00","note":null},{"source":"epss","external_id":"CVE-2021-20022","url":"https://api.first.org/data/v1/epss?cve=CVE-2021-20022","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-23T19:13:43+00:00","fetched_at":"2026-10-23T19:13:43+00:00","note":null},{"source":"nvd","external_id":"CVE-2021-20022","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-20022","severity":null,"published_at":"2021-04-09T18:15:13+00:00","modified_at":"2026-10-01T21:17:15+00:00","first_seen_at":"2026-10-23T21:57:34+00:00","fetched_at":"2026-10-23T21:57:34+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}